Supported shear with reversible linear drive and in-feed table therefor

ABSTRACT

A bladeless shear for bar stock and tubing comprising axially adjacent stationary and moving dies which receive the stock and produce a shearing action by relative lateral displacement. A linear actuator or an electric motor produces the mechanical movement to rotate the drive wheel in alternatingly opposite directions. A mandrel for insertion into the tube is disclosed as well as an hydraulic tube clamp and an adjustable in-feed table.

This application is a division of Ser. No. 08/941,811 filed Sep. 30,1997 now U.S. Pat. No. 6,352,012.

INTRODUCTION

This invention relates to bladeless shearing of linear stock such asstainless steel tubing and bar stock and, more particularly, to a devicewhich achieves the shearing of stock by causing elliptical, lateraltranslation of a section of the stock relative to an axially adjacentsection.

BACKGROUND OF THE INVENTION

In U.S. Pat. No. 4,635,514 “Elliptical Shearing Apparatus”, issued Jan.13, 1987 to Alexander Borzym, there is disclosed a bladeless device forshearing linear stock, such as bar stock and tubing, by causing asection of the stock to translate laterally through an elliptical pathrelative to the axially adjacent stock. As is more fully disclosed inthe aforesaid patent, this is achieved through the use of a large, steelbody referred to as a “die holder” having a central, die-like apertureformed therein which is adapted to receive and precisely surround thelinear stock. One side of the die holder is pinned to permit pivotal andlimited lateral motion. The other side is connected to a drive mechanismconsisting of a large electric motor driving a flywheel at constantspeed and a clutch and brake mechanism for selectively and momentarilyimparting orbital motion to the die holder. Orbital motion of the dieholder around the mechanical drive center produces a unidirectional,elliptical translation of the stock receiving die which lies between thedrive center and the pinned end of the die holder. The amplitude of theelliptical motion is a function of the amplitude of the orbital drivemotion and the geometric location of the die within the die holder body.

By placing a fixed die also having a stock-receiving apertureimmediately axially adjacent to the moveable die, a scissors-likeshearing action is produced on a length of stock which is insertedthrough the two aligned dies; the shear line is defined by the matingplane of the two dies.

There are numerous advantages to a shear of this type relative tocutoffs using blades or other cutting implements. The principaladvantages are the elimination of the cutting implement as a perishablecomponent and the conservation of material in the work piece; i.e., sawblades and guillotine blades remove a section of material approximatelyequal to the thickness of the blade each time it passes through thestock. The resulting loss of material from the stock is significant,particularly where short lengths and high cutting rates are employed.

Another advantage is the quality of the “cut” which can be achieved inthe use of the bladeless shear in connection with stock of very hardmaterial such as stainless steel. Blade type cutoffs are known to causedistortion; e.g., burrs and/or dents in the cut tube ends, and very highblade wear when used with hard materials such as stainless steel. Thebladeless shear cutoff actually excels when used with materials of thistype.

SUMMARY OF THE INVENTION

The present invention provides a novel and advantageous table suitablefor supporting lengths of tubular stock of varying diameters being fedinto a supported shear where the tubular stock is severed into desiredlengths. The table comprises a pair of parallel spaced apart rods,preferably of cirular cross section, symmetrically arranged on oppositesides of the intended path of the stock. The rods are pivotallyconnected to links which in turn are pivotally connected to convergingsurfaces of a support block such that coordinated rotation of the linkschanges the spacing between the support rods without disturbing theparallel relationship between them.

In the preferred embodiment, the angular positions of the links aredetermined by turnbuckles which are connected between the tops of thelinks and a support block which can be clamped to a support surface inany of an infinite number of longitudinal positions such that angularposition of the links can be controlled either by adjusting theturnbuckles or adjusting the clamp block.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a bladeless shear device having anin-feed table which feeds tubing onto a mandrel rod and into the shearfrom left to right;

FIG. 2 is a simplified schematic drawing of an adjustable stroke tubeshear and linear motor drive useful in explaining the concept of thepresent invention;

FIG. 3 is a perspective drawing of the bladeless shear device of FIG. 1enlarged to show detail;

FIG. 4 is a front view of the bladeless shear machine illustrating thearrangement of the stationary and orbital rams and the adjustableorbital drive;

FIG. 5 is a side view partly in section to show details of the lineardrive;

FIG. 6 is a cut away view of the ram and tooling portion of the deviceof FIG. 1 with the mandrel in place within a length of tubular stock tobe sheared;

FIG. 7 is a simplified view of the orbital ram and a portion of thedrive system useful in explaining certain dimensional relationships ofthe orbital drive function;

FIG. 8 is a schematic diagram of an hydraulic power system for producingoperation of the linear drive;

FIGS. 9A and 9B are end views of the in-feed table illustrating theadjustment for different tube sizes;

FIG. 10 shows a table detail for adjusting the spread between theelements on which the stock rests; and

FIG. 11 is a schematic drawing of the electric motor embodiment of thelinear drive.

DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENT General

Referring to FIGS. 1 and 3, there is shown a bladeless supported sheardevice 10 mounted on a rigid steel base 12 for shearing tubular stock 14which is fed into the device 10 with the help of an in-feed table 16which underlies and supports the stock. Device 10 comprises a die holderassembly including a stationary ram 18, an axially adjacent orbital ram20 and a stock clamp 22. The orbital ram 20 comprises a drive wheel 24which is variably eccentrically driven by an hydraulic linear actuatorassembly 26 through a drive shaft housing 28. Base 12 includes agenerally planar top 30 of convenient work height for the device 10which is matched to the height of the in-feed table 16.

The device 10 of FIGS. 1 and 3 is described herein as applied to theshearing of tubular stock of relatively hard; i.e., low ductility,material such as stainless steel. However, it is to be understood thatwith appropriate die tooling, the device 10 can be used to shear a widevariety of elongate stock including solid or bar stock, round tubing,square, triangular, oblong, rectangular, and polygonal tubing andfabricated shapes, both open and closed, of many shapes and materials.

The apparatus of FIG. 1 includes a mandrel 32 (see FIG. 6) which isinserted into the stock 14 from the end most distal from the device 10by way of a small diameter rod 34 of adjustable length and which isadapted to be held in position during a shearing operation by means of amanually releasable clamp 36 carried on the end of in-feed table 16. Theconstruction of operation of the device 10 and table 16 will bedescribed on the premise that the stock 14 is being re-cut to lengths,constant or variable, which are selected fractions of the original stocklength in preparation for a fabrication operation utilizing the re-cutlengths. It is further premised that the stock 14 is beingintermittently fed into the ram assembly of the device 10 and thatactuation of the ram assembly to produce the shearing action occurswhile the stock 14 is stationary. A suitable systems for automaticallyfeeding stock into the shear device 10 is described in copendingapplication Ser. No. 08/941,812, filed concurrently herewith in the nameof John J. Borzym as sole inventor, now U.S. Pat. No. 6,123,003 issuedSep. 26, 2000.

Referring now to FIGS. 2 and 7, a brief description will be made of theprincipal components of the bladeless shearing device 10 including thelinear drive 24, 26, 28 and the functions thereof in shearing thestainless steel tubular stock 14. It will be understood that a mandrelis not needed if the stock is solid and may not be needed if the stockis of an open shape or configuration which can be matched by dieopenings in the die holder assembly 18, 20.

As shown in FIG. 2, the stationary ram 18 is mounted on the base 12 andhas a circular die aperture 38 the shape of which conforms closely tothe external surface of the stock 14 and the central axis 40 of which isaligned with the longitudinal axis of the stock. Located in abutting,adjacent relationship to the stationary ram 18 is an orbital ram 20 acentral portion 42 of which is provided with a circular die aperture 44which, in the rest position of the ram 20, is axially aligned with theaperture 38 in the stationary ram 18 thereby to receive the tubularstock 14 and permit the stock to pass through the apertures 38 and 49 tothe desired extent. The diameter of aperture 44 is slightly larger thanthat of aperture 38. The actual shape of the orbital ram 20 is morerealistically illustrated in FIGS. 3, 4 and 7, the shape of FIG. 2 beingchosen merely for purposes of schematic description; i.e., the shapeshown in FIG. 7 provides more strength and rigidity which is required ofa tube shearing operation in actual practice. Moreover, the ram 20 isshown in FIG. 7 to include a replaceable tool-steel insert 46 whichdefines the die aperture 44.

The right-hand side of the orbital ram 20, as shown in FIGS. 2 and 7, isprovided with a slot 47 which receives in sliding relationship therein apivot block 48 which is pivotally mounted on a bearing flange 50 bymeans of a shaft 51 for pivotal motion about an axis 52 which isparallel to the axis 40 of the apertures 38 and 44. Bearing flange 50 iswelded to base 12. The lateral clearances between the block 48 and theslot 47 permit limited lateral movement of the ram 20 relative to theflange 50 for reasons to be explained.

At the left end, as seen in FIGS. 2 and 7, the ram 20 fully surroundsand accommodates therein the drive wheel 24 and a bearing 25 therefor.The wheel is rotatably driven through a shaft 54 supported on themachine base 12 by a fixed support 56. Shaft 54 carries a pinion 58which meshes with the teeth of a vertical rack 60 which is alternatelydriven in opposite directions by hydraulic cylinders 62 and 64 which arepart of the linear actuator assembly 26.

The shaft 54 is assembled to wheel 24 by way of an integral nut 66 whichis trapped within a semi-diametral slot 70 in wheel 24. The nut 66 isthreaded to receive a screw shaft 68 having upper and lower thumb wheels72 and 74. Rotation of the shaft 68 causes movement of the nut 66 alongthe shaft such that the center of shaft 54 can be displaced to anydesired degree from the geometric center of the wheel 24, which centeris marked in FIG. 2 by a cross symbol. It can readily be seen that whenthe center of shaft 54, i.e., the wheel “drive center,” coincides withthe geometric center of the wheel itself, rotation of the wheel causesno motion of the ram 20 relative to base 12. However, when the drivecenter is displaced from the geometric center of the wheel 24 as shownin both FIGS. 2 and 7, an eccentric drive is created which forces thecenter of the ram 20 to follow an orbital path around the center line ofthe shaft 54. This eccentric motion, although orbital about the shaftcenterline, is elliptical in the area of ram portion 42 as hereinafterexplained.

In the schematic examples of FIGS. 2 and 7, the distance from axis 52 tothe center line of shaft 54 where the slot 70 is vertical is twice thedistance from the axis 52 to the axis 40. To state it otherwise, thecenterline of the tooling die aperture 44 is exactly midway between thecenter of wheel 24 and the pivot shaft 50. Accordingly, the radialamplitude of the vertical component of displacement of the axis 40 whenthe eccentric wheel drive is operative is one-half of the radialdisplacement of the wheel center+from the center of the shaft 54.However, the amplitude of the lateral displacement of the ram 20 in allplaces is equal to the radial amplitude of the orbital motion about thecenter of shaft 54, the clearances between the block 48 and slot 46permit this lateral translation. Since the amplitude R1 of the lateralram displacement is twice the amplitude R2 of the vertical displacementat axis 40, the motion of the ram 20 about the axis 40 is ellipticalrather than circular. The amplitude R1 is called the “stroke” and isvaried by varying its degree of drive eccentricity through thumb wheels72 and 74.

In operation, the apparatus schematically illustrated in FIG. 2 is setup with the nut 66 displaced from the geometric center of the drivewheel 24 by a distance which is approximately equal to the wallthickness of the tubular stock 14. In addition, the apertures 38 and 44are arranged so that they are coaxial; in the actual device hereinafterdescribed this requires that the stationary ram 18 be adjustable invertical position relative to the base 12. The stainless steel tubularstock 14 is fed through the concentric tooling apertures 38 and 44 untilthe desired shear line of the stock is co-extensive with the plane inwhich the inner diameters of the apertures 38 and 44 meet; i.e. thecircular “seam” between the aperture 38 of the stationary ram 18 and theaperture 44 of the orbital ram 20. A mandrel such as 32 in FIG. 6 isplaced within the stock 14. As hereinafter explained, the mandrel playsan integral part in the shearing action.

At this time, one of the hydraulic cylinders 62 and 64 is actuated todisplace the rack 60 sufficiently to rotate pinion 58 about onerevolution. The orbital motion imparted to the wheel 24 by the eccentricdrive produces elliptical movement of the shearing ram 20 relative tothe stationary ram 18 and the section of the tubular stock 14 within andforward of the aperture 44 is displaced elliptically relative to theaxially adjacent section of tubular stock which is held fixed within theaperture 38 of the stationary ram 18. This relative elliptical motion issufficient to shear or break the material of the tubular stock 14cleanly in the plane which is co-extensive with the seam between theapertures 38 and 44. Cleanly shorn tube ends requiring little or nosecondary operations are the result.

The tubular stock 14 is thereafter advanced until the next shearinglocation is centered between the stationary and fixed rams 18 and 20,respectively, and the opposite cylinder 62, 64 is actuated to drive thewheel 24 via the shaft 54 through one revolution in a direction oppositeto that of the first operation. The intermittent bi-directionaltranslation of the wheel 24 and the ram 20 tends to distribute wear inthe area of the apertures 28 and 44, commonly embodied as hereinafterdescribed by expensive alloy steel tooling, around the surfaces of theapertures in a relatively uniform way thereby to substantially improvetooling life relative to the unidirectional drive which was used in theprior art device described above.

Referring now to FIGS. 3-10, a first illustrative embodiment of theinvention suitable for commercial application will be described indetail.

The in-feed table 16 is shown in FIGS. 9A, 9B and 10 to comprise a pairof spaced parallel solid steel bars 76 and 78 of circular cross sectionpivotally secured at each of several spaced locations to identical setsof links 80 and 82, respectively, which are pivotally connected to thebeveled faces of a series of spaced support blocks 84 for rotation aboutintersecting non horizontal axes 85 and 87. The blocks 84 are located atregular intervals along a beam 86 which is carried on fabricated steellegs 88. As shown in FIGS. 9 and 10, the links 80 and 82 may beselectively pivoted about axes 85 and 87 to adjust the relative spacingbetween the rods 76 and 78 as well as the elevation thereof thereby tolocate the centerline of the stock 14 such as to align it with the axisof apertures 38 and 44 as described above. To further explain, the links80 and 82 are pivotally mounted to the upwardly converging faces of theblocks 84 to rotate about axes 85 and 87 whenever the turn-buckles 146and 148 are lengthened or shortened and/or are adjusted in position bymeans of the mechanism 150, 156 and 160. The pivot points for the links80 and 82 are near the bottoms of the upwardly converging faces of block84 where those faces are farthest apart. When the longer dimension ofthe lengths 80, 82 is most upright, as shown in FIG. 9A, the rest bars76, 78, being pivotally mounted to the tops of links 80 and 82, arecloser together to accommodate smaller diameter tube 14. When the links80, 82 are rotated about axes 85 and 87 to a less upright orientation,the tops of the links and the pivot axes 85 and 87 diverge, thuswidening the spacing between the bars 76, 78 as shown in FIG. 9B toaccommodate larger diameter tube. The mechanism 150, 152, 154, 156, 158,160 allows simultaneous adjustment of the angular positions of bothlengths 80 and 82 whereas the turn-buckles 146, 148 allow individualadjustments. The bars 76 and 78, although shown as if circular (round)cross-section and of a diameter which is less than that of the stock 14,may be of other shapes and sizes. It is believed desirable, however, touse a bar shape which, in combination with the stock shape, produces atangential contact for minimizing contact area.

The table 16 is arranged so as to feed the tubular stock 14 onto anotched rest block 90 which is carried within a large steel frame 92mounted to the stationary ram 18 by way of a bolt 94 which correspondsto pin 51 in FIG. 2 and passes through a hole in bearing flange 50 shownin FIG. 4. The axis of the bolt 94 corresponds with the axis 52 shown inFIG. 2; i.e., it is the lever axis or fulcrum about which the orbitalram 20 is caused to pivot by operation of the linear drive. Frame 92carries the hydraulic cylinder 22 having a vertically extending plunger98 disposed immediately over the noted support block 90 so as toeffectively clamp the portion of the tubular steel stock 14 in whichmandrel 32 is located during a shearing operation. The clamp cylinder 22stabilizes the mandrel 32 and prevents the stock 14 from whipping duringthe shear operation; such whipping action can produce the undesirableresult of non-square tube ends.

The elevation of the clamp block 90 is adjusted to accommodate theparticular stock by way of an adjustable leg 100 which extendsvertically through an integral portion of the frame 92, as shown in FIG.3 and has suitable locking means at 102.

The stationary ram 18 lies between and immediately adjacent each of theframe 92 and the orbital ram 20 and is provided with a tool steel insert46 having formed therein the aperture 44 which closely surrounds andholds the tubular stock 14 during the shearing operation. To permitalignment of the apparatus as hereinbefore described and to accommodatetubular stock of varying outside diameter, the stationary ram 18 is alsomounted on the bolt 92 for pivotal motion about the axis 52 which is thecommon pivot axis to the frame 92 and the fixed ram 18. A support leg104 is mounted on the stationary ram 18 and extends in adjustablethreaded relationship into the base 12. A compression spring 106 urgesthe right side of the ram 18 in the counter-clockwise direction as shownin FIG. 3 to maintain tension in the bolt 104. The frame 92 and thestationary ram 18 are preferably fastened together so they can be movedand/or adjusted as a unit by through bolts 108 and 110 which extendparallel to the axis of the tubular stock 14. The nuts on bolts 108 and110 are tightened once proper alignment has been achieved.

As best shown in FIG. 5, the transmission housing 28 contains a steppedsteel shaft 54 having two different but relatively large outer diametersseated in bearings 112 and 114 for rotation about the central axis ofthe shaft 54. The right-hand end of the shaft 54, as shown in FIG. 5, issplined to receive the pinion 58 shown in FIG. 2 but removed for clarityin FIG. 5. Pinion 58 meshes with the racks of the two-way linear driveas hereinafter described. The left side of the shaft 54 is of polygonalconfiguration to define nut 66 and extends into the slot 70 in the drivewheel 24 to engage the threaded shaft 68 disposed therein. A plate 116covers the slot 70 during operation as shown in FIG. 5.

Looking now to FIG. 6, the details of the mandrel 32 which is disposedwithin the tubular stock 14 during shearing operations to preventcollapse and/or deformation of the stock wall will be described. Themandrel 32 is a bullet-shaped steel body mounted on shaft 34 whichpermits the mandrel to extend through a long length of tubular stock andprecisely located so that critical portions of the mandrel correspond inlocation with the shear line at the interface between the shear toolinghereinbefore described. The shaft 34 terminates in a flared end collar112 having a threaded axial bore which receives therein the threaded endof a rod 114 to permit length adjustments. Nut 116 locks the threadedrod 114 relative to the collar 112 when the appropriate length isachieved.

The body of mandrel 32 is essentially cylindrical and its internaldiameter closely approximates that of the interior of the tubular stock14. It is long enough to lie between the dies 18 and 20 and to liewithin the stock 14 under the clamp 22. The distal end of the mandrel 32is provided with an assembly which comprises a threaded center shaft, afixed annulus 120, a laterally moveable annulus 118, a cap 124, acompression spring 126, a cam collar 128, and a nut 122. Cam collar 128has a beveled external bearing surface which mates with a similarbeveled interval surface in annulus 120. Spring 126 permits the collar128 to move radially and axially at the same time against the bias ofspring 126. The mating plane or “seam” between fixed annulus 120 andmoveable annulus 118 must correspond precisely to the interface seambetween the stationary and orbital rams 18 and 20, respectively, duringa shearing operation so that one section of stock 14 can move laterallyof the adjacent section for shearing purposes.

Looking now to FIG. 8 an hydraulic control system for programming andcontrolling operation of the linear drive will be described. Pressure(P) and Tank (T) lines 132, 134 are connected in a loop fashion throughhydraulic spool valves 136, 137 and 138 each of which is equipped with aconventional internal spool to permit high pressure and tank pressure tobe gradually applied to either of the output lines from those valves ina controlled and selectable fashion. Valve 136 is a proportional valueand is connected via output lines 139 and 140 to the hydraulic cylinders62 and 64 to effect displacement of the internal pistons/racks 65 and 66respectively. These racks engage the teeth of the orbital wheel drivepinion 58 which resides in a box 130 lubricated by pressure tapped fromline 139 through a regulator 141.

In the configuration shown in FIG. 8 high pressure (P) will be appliedto the top of cylinder 62 to initiate a shear cycle and tank pressure(T) simultaneously applied to the top of cylinder 64 to maintain a smallresidual pressure against the top of racks/pistons 66. As a result thehigh pressure drives the racks/pistons 65 downwardly as shown in FIG. 8rotating the pinion 58 counter clockwise and driving the right handpiston 66 through the pinion 58 upwardly against the slight residualtank pressure. This maintains the teeth of the pinion gears inengagement with the same side of the rack convolutions at all times andeliminates backlash which might otherwise make stopping the orbitalwheel at the dead center position more difficult and/or impossible. Todrive the piston/racks 65, 66 in the opposite direction the spool invalve 136 is shifted by an appropriate input signal to a position whichreverses the pressure value on the output line. The cylinders 62 and 64are provided with precisely adjustable mechanical stops which correspondto and actually define the top-dead-center position.

Valve 137 is used to selectively “jog” the pistons for any of a varietyof operations including test and die assembly procedures. Valve 138 isavailable to provide a torque boost in the event a particularly hard orheavy wall thickness material is to be shorn.

It will be apparent to those skilled in the hydraulic control arts thatthe valves 137 and 138 are controlled by solenoids which in turn arecontrolled from a conventional control panel having push buttons,switches, and similar input/output devices. Valve 136 is preferablycontrolled by hydraulic pressure through a pilot line 131.

Looking again to FIGS. 9A, 9B and 10, the in-feed table 16 is shown tocomprise solid steel rods 76 and 78 forming tube rests and mounted inpivotal links 80 and 82 The angles of the links 80, 82 relative to theblock 82 are determined individually by turnbuckles 146 and 148connected to opposite sides of slotted slide block 150 mounted on base152. The longitudinal portion of block 150 relative to base 152 can beadjusted via Allen-head screw 154 to produce a fast and simultaneousadjustment of the angular positions of the links 80 and 82. The selectedportion is then maintained or locked-in by clamp lever 156 attached toclamp head 158 the integral bolt of which extends downwardly through theset 160 into a tapped hole in base 152. Individual fine adjustment ofthe angular positions of links 80 and 82 can be accomplished by means ofthe turn-buckles 146 and 148. It will be noted from FIGS. 9A and 9B thatthe included angle between the contact points of the rests 76, 78 andthe tube 14 remains nearly the same over a range of adjustments; i.e.,both a small tube as shown in FIG. 9A and a larger tube as shown in FIG.9B contact the bars 76, 78 at the 5 o'clock and 7 o'clock positions.Thus, the in-feed table rests can be narrowed or spread without creatinga shallow unstable tube rest.

Table 16 underlies and supports the tubular stock 14 as it is fed intothe shear device 10. By supporting the tubular stock, table 16 alsosupports the mounted rod 34 shown in FIG. 1 and prevents it fromsagging. To this end, cast iron forms 35 are mounted on the rod 34 at 4foot intervals and have outside diameters which closely approximate theinside diameter of the stock 14 to hold the rod 34 straight and preventmovement of the mandrel relative to the shear plane. Thisinstrumentality greatly increases the life of the tooling. The materialof forms 35 can be other than cast iron but is preferably somewhatsofter than the material of the work piece so as to be “sacrificial” inthe event of interference which might otherwise mar the work piece.

In operation, a first shearing stroke is initiated by opening valve 136to actuate cylinders 62 and 64 in the manner described above. Thisrotates the pinion 58 one revolution of the drive wheel 24. On the nextcycle, the cylinders 62 and 64 are actuated in the opposite direction byopening valve 136 to apply “P” and “T” pressures to opposite cylinders.

A suitable apparatus for implementing the linear drive including thehydraulic cylinders, the racks, and the pinion, as well as the highpressure hydraulic pump 132 and its power supply is available fromFLO-TORK, Inc. of Orrville, Ohio 44667. FLO-TORK, Inc. refers to theproduct as an hydraulic rotary actuator. FIG. 11 illustrates analternative power source in the form of a reversible electric motor 170connected to the shaft 54 in unit 28 through a reduction gear unit 171.The assembly 28 is otherwise the same as the arrangement shown in FIG.5. The motor 170 is preferably of the reluctance type and may beprecisely controlled as to direction and stopping location by meanswhich will be apparent to persons familiar with feedback positioncontrol systems.

What is claimed is:
 1. An adjustable support for tubular stock comprising: a pair of parallel stock support bars spaced apart by a distance which is less than the stock diameter whereby the stock rests between and in parallel contact with both of the bars; and means for varying the spacing between said bars.
 2. Apparatus as defined in claim 1 wherein the means for varying comprises a plurality of pairs of links pivotally connected to said bars and to spaced support blocks having upwardly converging, beveled lateral surfaces, and means for selectively variably rotating said links about respective non-parallel pivot axes passing through said lateral surfaces to individually position said bars.
 3. A support apparatus for tubular stock comprising: a base; a support block on the base and having laterally opposite upwardly converging lateral plane surfaces; first and second parallel, spaced apart stock support bars adapted to receive the stock therebetween and in parallel contact therewith; first and second links pivotally connected between respective surfaces of the support block the base and the first and second support bars, respectively; first and second turnbuckles each having one end connected to a respective link; and means adjustably connecting the other end of each of the turnbuckles to the base for selectively rotating the links relative to the base to vary the spacing between the parallel bars.
 4. A support apparatus as defined in clam 3 wherein the stock support bars are essentially round in cross section.
 5. In a bladeless shear device of the type having first and second tools aligned with a work piece axis and means for causing orbital motion of one of the tools relative to the other; an actuator having a linearly translating drive component; and means for converting the linear translation of the drive component into orbital motion of said one tool. 